Optimization of heat regulation in a device comprising a fan

ABSTRACT

The invention concerns a device ( 1 ) comprising: at least one component ( 7 ), at least one fan ( 4 ) for regulating the temperature of the component ( 7 ), a processor ( 5 ), and at least one temperature sensor ( 3 ), characterised in that the processor ( 5 ) is configured to control the direction of rotation of the fan ( 4 ) on the basis of the temperature of the component ( 7 ) measured by the temperature sensor ( 3 ), so as to regulate the temperature of the component ( 7 ) and the noise generated by the fan ( 4 ). The invention also concerns a method for regulating the temperature in this device.

GENERAL TECHNICAL FIELD

The invention relates to a device, the temperature control whereof isprovided for by a mechanical ventilation system.

PRIOR ART

Electronic devices conventionally include at least one fan for controlof their temperature.

Effective temperature control is indispensable for maintaining theperformance of the device.

Indeed, heating of the components of the device often causesdeterioration of the performance of the device.

This is for example the case in electronic devices including a lightemitting system, for display or projection of an image. In particular,the quality of the image displayed or projected by the light emittingsystem, and in particular its sharpness, depend on the propertemperature regulation of the light emitting system. A too hightemperature of the components of the light emitting system degrades thequality of the produced image.

In the prior art, the temperature control of at least one component ofthe electronic device is managed by a processor which controls therotation speed of the fan depending on the temperature of the component.

This rotation speed has in particular from one to three levels,depending on the temperature of the component.

However, with this kind of control, this type of device is very noisy.In particular, the noise generated by the device increases with theheating of the device.

When the device is heavily loaded (for example in the case when itdisplays or projects images of higher quality), or when the device isplaced in an environment with a high temperature, the noise generated bythe device is a maximum, which discourages and inconveniences the users.

Some devices reduce the noise by reducing the rotation speed of the fan,but this is accomplished to the detriment of the performance of thedevice.

In addition, in the case of portable devices, supposed to be mobile andusable in all circumstances (meetings, trips), the user can not use thedevice in an optimal and comfortable manner.

PRESENTATION OF THE INVENTION

To compensate for these shortcomings, the invention proposes a deviceincluding at least one component, at least one fan to control thetemperature of the component, a processor, and at least one temperaturesensor, characterized in that the processor is configured to control thedirection of rotation of the fan according to the temperature measuredby the temperature sensor, so as to control the temperature of thecomponent and the noise generated by the fan.

This makes it possible to control the temperature of the componentswhile minimizing the noise generated by the fan.

The invention is advantageously complemented by the following features,taken alone or in any one of their technically possible combinations:

-   -   the device also includes at least one outer opening of which the        size is adjustable, for passing a stream of air, the processor        being configured to control the direction of rotation of the fan        and the size of the outer opening according to the temperature        of the component;    -   the processor is configured to increase the size of the outer        opening with an increase in the temperature of the component;    -   the processor is configured to control the speed of rotation of        the fan according to the temperature of the component;    -   the fan has, for a given rotation speed:        -   a direction of rotation giving a noise with a first            amplitude,        -   another direction of rotation generating a noise with a            second amplitude, greater than the first,    -   the processor being configured to select the direction of        rotation of the fan generating the noise with the second        amplitude when the temperature of the component exceeds a        threshold;    -   the processor is configured to select the direction of rotation        of the fan generating the noise of a second amplitude when the        size of an outer opening of the device is a maximum;    -   the device includes a light emitting system which includes light        emitting elements and optical elements for projection of an        image, the component of which the temperature is controlled        corresponding to the optical elements;    -   the device is a portable image projector.

The invention also relates to a temperature control process in a devicesuch as that described previously, including the step consisting ofcontrolling the direction of rotation of the fan according to thetemperature as a function of the temperature of at least one componentof the device measured by the temperature sensor, so as to control thetemperature of the component while minimizing the noise generated by thefan.

The method can also include the step according to which, during theincrease in the temperature of the component, the processor controls thesize of an outer opening of the device up to its maximum size, thenselects the direction of rotation of the fan according to thetemperature of the component.

The different embodiments of the invention offer numerous advantages.

Thus, the device allows optimization of the compromise between thecontrol of temperature, synonym of good performance for the device, andreduction in noise for the user. For example, in the case of a deviceincluding a light emitting system configured for displaying orprojecting images, the display and projection performance are ensuredwhile still reducing noise.

The device is therefore more pleasant to use.

In addition, the device allows simple and optimized control oftemperature, while still maintaining a reduced noise level.

The solution is effectively adapted to devices containing a fan, withoutmaking a complete review of their architecture necessary.

PRESENTATION OF THE FIGURES

Other features, aims and advantages of the invention will be revealed bythe description hereafter, which is purely illustrative and notlimiting, and which must be read with reference to the appended drawingswherein:

FIG. 1 is a schematic representation of an embodiment of a deviceaccording to the invention;

FIG. 2 is a schematic representation of another embodiment of a deviceaccording to the invention;

FIG. 3 is a schematic representation of an embodiment of a controlmethod according to the invention;

FIG. 4 is a schematic representation of an exemplary embodiment of acontrol method according to the invention.

DETAILED DESCRIPTION Device

Represented schematically in FIG. 1 is an embodiment of a device 1according to the invention. This device 1 is an electronic device, thetemperature whereof must be controlled.

The device 1 includes at least one component 7. The component 7 is forexample an optical and/or electronic type component, which can provideone or more functions for the device 1.

For example, in the embodiment of FIG. 2, the device 1 includes a lightemitting system 2, configured for displaying an image, and/or forprojecting an image.

This is for example a screen for displaying an image, or a system forprojecting an image toward a projection surface such as a wall or anyother suitable surface.

In the example illustrated in FIG. 2, the light emitting system 2includes light emitting elements 11 and optical elements 12. Theelements 11 are for example light emitting diodes (LEDs) of the threebasic colors (red, green blue), and the optical elements 12 are a set ofmicro-mirrors the position and the inclination whereof are controlledelectronically. The optical elements 12 can for example be integratedinto a micro-chip.

The elements 11 emit one or more light rays toward the elements 12,which project the rays toward a projection surface, for projecting theimage. This type of projector is known in the art.

In the example of FIG. 2, the component 7 of which the temperature is tobe controlled is a component of the system 2, such as for example theoptical elements 12.

The component 7 can also be any other component whose temperature needsto be controlled so as to maintain the performance of the device 1, anelectronic card, processor, etc.

The device 1 includes at least one fan 4 for controlling the temperatureof the component 7. If applicable, several fans 4 can be present in thedevice 1.

The device 1 also includes a processor 5. This can be the main processorof the device 1, configured to manage the different electronic functionsof the device 1 (interaction with the user, managing loading, managingapplications, etc.), or a processor dedicated to implementing thetemperature control process described hereafter.

Managing the temperature of the emission system 2 is crucial forensuring the performance of the device 1.

This temperature can particularly be measured by one more temperaturesensors 3, positioned in or in proximity to the component 7.

The temperature of the emission system 2 depends mainly:

-   -   on the ambient temperature to which the device 1 is subjected;    -   on the phase of operation of the device 1 (starting phase, in        operation, number of tasks carried out by the device, complexity        of tasks, etc.).

In particular, in operation, the temperature of the component 7 has atendency to increase.

However, in general, an increase in temperature of the component 7degrades the performance of the device 1.

Moreover, the increase in the speed of rotation of the fan 4, to reducethe increase in temperature of the component 7, increases the noisegenerated by the device 1.

The processor 5 is configured to control the direction of rotation ofthe fan 4 depending on the temperature of the component 7, so as tocontrol the temperature of the component while minimizing the noisegenerated by the fan.

In particular, the processor makes it possible to reduce the temperatureof the component 7 while still minimizing the noise generated by the fan4. The compromise between control of temperature and reduction of noiseis thus optimized, which allows the performance of the device 1 to bemaintained while still reducing the noise generated.

For example, in the example illustrated in FIG. 2, wherein the component7 is part of the light emitting system 2, the increase in temperature ofthe light emitting system 2 degrades the lighting effectiveness of thesystem 2.

Thus the quality of the image produced, like its sharpness or itsclarity, deteriorates with the increase in temperature of the lightemitting system 2. This results particularly from performance of thelight emitting elements (LEDs) with temperature.

Thanks to control of the direction of rotation of the fan 4 by theprocessor 5, the temperature of the light emitting system 2 iscontrolled while reducing the noise generated by the fan 4.

For a given rotation speed, the fan 4 generates a smaller noise in onedirection of rotation compared to the other direction of rotation.

Indeed, depending on the direction of rotation of the fan 4, the streamof air is aspirated or blown. The path of the flow of air in the device1 is therefore different, which creates a different aerodynamic noise.

Likewise, given the path of the stream of air varies depending on thedirection of rotation of the fan, temperature control of the component 7varies depending on this direction of rotation. In particular, theinfluence of the direction of rotation of the ventilator 4 on thecontrol of temperature depends in particular on the relative position ofthe fan 4 with respect to the component 7.

Generally, the direction of rotation of inducing the maximum noise isthat which also allows the best reduction in the temperature of thecomponent 7.

As mentioned previously, the fan 4 has, for a given rotation speed, arotation direction generating a noise with a first amplitude, andanother direction of rotation generating a noise with a secondamplitude, greater than the first.

According to one possible aspect of the control implemented by theprocessor 5, it is configured to select the direction of rotation of thefan 4 generating the noise of a second amplitude when the temperature ofthe component 7 is greater than a threshold.

Below this threshold, the processor 5 retains the rotation directiongenerating a smaller noise of the first amplitude.

Besides the ventilator 4, the device 1 can include at least one outeropening 10 of which the size is adjustable. It can also consist of aplurality of outer openings 10.

According to one example, the processor 5 controls a motor 14 whichcontrols the size of the outer opening 10 (or of the plurality ofopenings 10). The outer openings 10 include for example an elementsliding in front of a recess, the translation whereof controls the sizeof the openings 10.

These outer openings 10 allow the circulation of a stream of air towardand from the outside of the device 1.

The outer openings 10 can be positioned on an edge of the device 1, orover the entire perimeter of the device 1.

According to one embodiment, the processor 5 is configured to controlthe direction of rotation of the fan 4 and the size of the outeropenings 10 according to the temperature of the component 7.

This dual control makes it possible to manage more accurately thecompromise existing between the temperature of the component 7 and thenoise generated by the fan 4, because another control parameter isavailable (size of the openings 10).

According to a particular example, the processor 5 controls, besides thesize of the openings 10, the profile of the outer openings 10, using themotor 14.

Different controls can be implemented in the device 1 for controllingtemperature. These controls can be combined, be partially used, or notbe used.

According to one aspect, the processor 5 is configured to increase thesize of the outer openings 10 with an increase in the temperature of thecomponent 7.

As will be understood, the increase in size of the outer openings 10makes it possible to reduce the temperature of the component 7, thanksto circulation of a stream of air in the device 1.

According to another aspect, the processor 5 is configured to controlsimultaneously the direction of rotation of the fan 4 and its rotationspeed, depending on the temperature of the component 7.

According to yet another aspect, the processor 5 is configured to selectthe direction of rotation of the fan 4 generating the noise with asecond (maximum noise) when the size of the outer openings 10 ismaximum. This means that the processor 5, when controlling thetemperature of the component 7, first controls the increase in size ofthe outer openings 10. Once this maximum size is reached, the processor5 controls the direction of rotation of the fan 4 and, if applicable,the rotation speed of the fan 4.

The device 1, which includes the component 7, can for example be aportable image projector. In this case, it includes a light emittingsystem 2.

This type of projector is transported by the user, like a USB key, andallows him to project images in different circumstances.

It can also consist of other portable devices requiring temperaturecontrol and a reduction in operating noise.

Without limitation, it can also consist of a USB key, a photographicdevice, a camera, a computer, a projector or a portable telephone,including one or more components whose temperature must be controlled.

Examples of Control

In FIG. 3, a temperature control method in the device 1 describedpreviously includes in particular the step E2 consisting of controllingthe direction of rotation of the fan 4 according to the temperature ofat least one component 7 of the device 1, so as to control thetemperature of the component 7 while minimizing the noise generated bythe fan 4. The temperature of the component 7 is measured by theaforementioned temperature sensor 3 and transmitted to the processor 5(step E1).

According to one aspect of the method, if the device 1 includes at leastone outer opening 10, the processor 5 controls the size of the opening10 up to its maximum size, then selects the direction of rotation of thefan 4 according to the temperature of the component 7.

A particular and non-limiting example of control is described hereafter,with reference to FIG. 4.

During starting of the device 1, the temperature T₂ measured (step E3)by the sensor 3 for the component 7 is low. The processor 5 selects thedirection of rotation of the fan 4 as the direction generating a firstmagnitude noise (low noise). The processor 5 keeps the outer openings 10closed (step E4).

When the temperature T₂ of a component 7 (such as for example theoptical elements 12 of the light emitting system 2) exceeds a thresholdT_(θ), the processor 5 begins to increase the size of the outer openings10 so as to reduce the temperature of the component 7 (step E5).

This makes it possible to maintain the performance of the device 1, likethe lighting effectiveness of the image projected by the system 2,despite the increase in temperature, while still minimizing the noise ofthe fan 4. As emphasized previously, the increase in temperaturedegrades the quality of the image in the case of a light emitting system2.

When the temperature T₂ of a component 7 (such as for example theoptical elements 12 of the light emitting system 2) exceeds a thresholdT_(β), where T_(β)>T_(θ), and the size of the outer openings 10 is amaximum, the processor 5 selects the direction of rotation of the fan 4generating a noise with a second amplitude (maximum noise, step E6).

This direction of rotation of the fan 4 makes it possible to furthercool the component 7. Although the direction of rotation of the fan 4 ismore noisy, this makes it possible to preserve the performance of thedevice 1, such as for example the quality of the image displayed orprojected by the system 2, even though the temperature T₂ of thecomponent 7 is high.

In this example, the speed of rotation of the fan 4 is assumed constant.However, this can also be controlled by the processor 5, and vary in theevent of an increase in temperature.

Likewise, simultaneous control of the size of the outer openings 10 andof the direction of rotation of the fan 4 (and/or its speed of rotation)can be implemented. In particular, it is not necessary that the openings10 have reached their maximum size to change the direction of rotationof the fan 4.

Likewise, the control implemented in the device 1 can depend on severaltemperature thresholds for the component 7, but also depend on severalmeasured temperatures.

In the example above, only the temperature of the component 7 has beentake into account (such as for example the optical elements 12) to theextent that it is the more representative temperature.

However, the temperature of other components 7 of the optical system 2can be taken into account in controlling the fan 4 and the openings 10.In the example of FIG. 2, the temperature of the light emitting elements11 can also be taken into account by the processor 5.

The invention allows optimized management of the compromise between theperformance of the device and the noise generated by the device. Itapplies particularly, but without limitation, to devices configured toproject or display an image.

1. A device (1) comprising: at least one component (7), at least one fan(4) for controlling the temperature of the component (7), a processor(5), and at least one temperature sensor (3), characterized in that theprocessor (5) is configured to control the direction of rotation of thefan (4) depending on the temperature of the component (7) measured bythe temperature sensor (3), so as to control the temperature of thecomponent (7) and the noise generated by the fan (4).
 2. The device (1)according to claim 1, further including at least one outer opening (10)of which the size is adjustable, for passage of a stream of air, theprocessor (5) being configured to control the direction of rotation ofthe fan (4) and the size of the outer opening (10) according to thetemperature of the component (7).
 3. The device (1) according to claim2, wherein the processor (5) is configured to increase the size of theouter opening (10) with an increase in the temperature of the component(7).
 4. The device according to one of claims 1 to 3, wherein theprocessor (5) is configured to control the speed of rotation of the fan(4) according to the temperature of the component (7).
 5. The device (1)according to one of claims 1 to 4, wherein the fan (4) has, for a givenrotation speed: a direction of rotation generating a noise with a firstamplitude, another direction of rotation generating a noise with asecond amplitude, greater than the first, the processor (5) beingconfigured to select the direction of rotation of the fan (4) generatingthe noise with the second amplitude when the temperature of thecomponent (7) is greater than a threshold.
 6. The device according toclaim 5, wherein the processor (5) is configured to select the directionof rotation of the fan (4) generating the noise with a second amplitudewhen the size of an outer opening (10) of the device (1) is a maximum.7. The device (1) according to one of claims 1 to 6, including a lightemitting system (2) which includes light emitting elements (11) andoptical elements (12) for projecting an image, the component (7) ofwhich the temperature is controlled corresponding to the opticalelements (12).
 8. The device according to one of claims 1 to 7, saiddevice (1) being a portable image projector.
 9. A method for controllingthe temperature in a device (1) according to one of claims 1 to 8,including the step consisting of controlling the direction of rotationof the fan (4) according to the temperature of at least one component(7) of the device (1) measured by the temperature sensor (3), so as tocontrol the temperature of the component (7) while minimizing the noisegenerated by the fan (4).
 10. The method according to claim 9, wherein,during an increase in temperature of the component (7), the processor(5) controls the size of an outer opening (10) of the device (1) up toits maximum size, then selects the direction of rotation of the fan (4)according to the temperature of the component (7).